Add Certificate via http fails if "-" is into the FQDN

[smarteshome2020]

Checklist

• Have you pulled and found the error with jc21/nginx-proxy-manager:latest docker image?
  • Yes
• Are you sure you're not using someone else's docker image?
  • Yes
• Have you searched for similar issues (both open and closed)?
  • No

Describe the bug
I try to get over Let`s Encrypt Certificate for eg. aa-test.example.com. This fails and the Test Results is witten the fqdn aatest.example.com.
It looks that the "-" is missing. I use the same FQDN with Nginx V 2.9.18 and it works.

Nginx Proxy Manager Version
V2.13.3

To Reproduce
Steps to reproduce the behavior:
Try to get a Certificate with a FQDN include "-" eg. aa-test.example.com

Expected behavior
Get a Certificate with V2.9.18

Screenshots

Operating System
Docker

Additional context